1. Field of the Invention
The present invention relates to touchscreens, touch panel displays, and their producing methods having advantages of low cost and high yield rate.
2. Description of the Prior Art
Touch panel displays incorporated with touch control and display technologies are widely used in electronic devices, such as cellular phones, digital cameras, computers, televisions, and so on. The user interface of such devices not only presents visual information but also allows a user to perform operations.
Touch panel displays can be divided into on cell touch panel displays and in cell touch panel displays. The in cell touch panel displays integrate touch sensors or photo sensors into the pixels of the liquid crystal display. The on cell touch panel displays include a touchscreen and a display, in which the former comprises touch sensors constructed by transparent patterns and the latter may be a liquid crystal display. Various types of touchscreen with different structures, such as resistance, capacitance, infrared rays, and surface acoustic wave type of touchscreen have been developed.
FIG. 1 is a simplified diagram showing configuration and fabricating method of a conventional capacitance type of touchscreen. Two substrates 10 and 11 are firstly provided. Then, an indium tin oxide (ITO) layer (not shown) and a metal layer (not shown) are formed on a surface of each substrate 10/11. The indium tin oxide layers and the metal layers are then etched to form a sensing pattern layer 12a and a conductive wire layer 13a on the surface of the substrate 10, and form a sensing pattern layer 12b and a conductive wire layer 13b on the surface of the substrate 11. The sensing pattern layers 12a/12b sense touch positions of the user, and the conductive wire layers 13a/13b connect the sensing pattern layers 12a/12b, respectively. After that, an adhesive layer 14 is employed to bond the two substrates 10/11 and thus form a touchscreen 1. Further, a printed circuit board 15, typically a flexible printed circuit 15, is used to electrically connect the conductive wire layer 13a/13b and conduct the signals of the sensing pattern layers 12a/12b to a controller (not shown). Typically, conductive circuits are laid on both surface of the printed circuit board 15, i.e., a double layer circuit layout, in which the conductive circuits of one surface connect to the conductive wire layer 13a, and the conductive circuits of the other surface connect to the conductive wire layer 13b. In addition, a printing method using conductive silver paste may be employed to form the conductive wire layers 13a/13b. 
The conventional method is complicated. In addition, as higher resolution of the touchscreen 1 is requested, the line width/line space of the sensing pattern layers 12a/12b and the conductive wire layers 13a/13b will get smaller and thus the yield rate is decreased due to the more precise configuration.
In view of the foregoing defects, a need is arisen that to provide novel touchscreens and their fabricating methods for improving the yield rate and lowering the cost.